I get a paper jam when trying to print from the Cassette

• The paper is too thick to feed from the Cassette. The official specification is up to 11.8 mil thickness. Workaround: feed from the top tray.
• The rollers are dirty. A build up on the rollers from paper coatings can occur, resulting in slippery rollers causing the jam. Clean all of the rollers with distilled water and brown coffee filter. See this thread for directions.